Nucleus-driven crystallization of amorphous Ge 2Sb 2Te 5: A density functional study

J. Kalikka*, J. Akola, J Larrucea, Robert O. Jones

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

62 Citations (Scopus)

Abstract

Early stages of nucleus-driven crystallization of the prototype phase change material Ge 2Sb 2Te 5 have been studied by density functional/molecular dynamics simulations for amorphous samples (460 and 648 atoms) at 500, 600, and 700 K. All systems assumed a fixed cubic seed of 58 atoms and 6 vacancies. Crystallization occurs within 600 ps for the 460-atom system at 600 and 700 K, and signs of crystallization (nucleus growth, percolation) are present in the others. Crystallization is accompanied by an increase in the number of "ABAB squares" (A: Ge, Sb, B: Te), and atoms of all elements move significantly. There is no evidence of cavity movement to the crystal-glass interface, as suggested recently, and the existence of Te-Te, Ge-Ge, Ge-Sb, and Sb-Sb ("wrong") bonds is an inevitable consequence of rapid crystallization.

Original languageEnglish
Article number144113
JournalPhysical Review B
Volume86
Issue number14
DOIs
Publication statusPublished - 22 Oct 2012
MoE publication typeA1 Journal article-refereed

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